1. Technical Field
The present invention relates to a wavelength conversion device, an illumination device, and a projector.
2. Related Art
In the past, there has been known a projector, which modulates light emitted from a light source device to thereby form an image corresponding to image information, and projects the image on a projection target surface such as a screen in an enlarged manner. As such a projector, there has been known a projector provided with a wavelength conversion device, which is excited by excitation light entering the wavelength conversion device to emit fluorescence (see, e.g., JP-A-2011-75898).
The projector described in JP-A-2011-75898 is provided with a light source unit, a display element, a projection optical system, and a cooling fan. The light source unit has alight source device for emitting blue light, alight source device for emitting the excitation light, and a fluorescence emitting device. The fluorescence emitting device is provided with a phosphor wheel, which is excited by the excitation light entering the phosphor wheel to emit the fluorescence, and a wheel motor for rotating the phosphor wheel.
In such a projector, the cooling fan directly blows the outside air against the phosphor wheel and the wheel motor as cooling air to cool the phosphor wheel and the wheel motor.
Incidentally, in the case in which the cooling gas blows against the fluorescence emitting device as in the projector described in JP-A-2011-75898, the cooling efficiency in the place, which the cooling gas blows against, is high, but the cooling efficiency in the place, which the cooling gas does not blow against, is low. Therefore, in the projector described in JP-A-2011-75898, there arises a problem that the fluorescence emitting device (the wavelength conversion element) cannot efficiently be cooled.